SC 37 Out Of Band Channels

---
name: "SC-37_out-of-band-channels"
description: "Employ the following out-of-band channels for the physical delivery or electronic transmission of [organization-defined] to [organization-defined]: [o"
category: "configuration"
version: "5.2.0"
author: "cyberstrike-official"
tags:
  - nist
  - sp800-53
  - rev5
  - sc-37
  - sc
tech_stack:
  - aws
  - azure
  - gcp
  - linux
  - windows
  - network
cwe_ids:
  - CWE-311
chains_with:
  - AC-2
  - CM-3
  - CM-5
  - CM-7
  - IA-2
  - IA-4
  - IA-5
  - MA-4
  - SC-12
  - SI-3
prerequisites: []
severity_boost:
  AC-2: "Chain with AC-2 for comprehensive security coverage"
  CM-3: "Chain with CM-3 for comprehensive security coverage"
  CM-5: "Chain with CM-5 for comprehensive security coverage"
---

# SC-37 Out-of-band Channels

## High-Level Description

**Family:** System and Communications Protection (SC)
**Framework:** NIST SP 800-53 Rev 5

Out-of-band channels include local, non-network accesses to systems; network paths physically separate from network paths used for operational traffic; or non-electronic paths, such as the U.S. Postal Service. The use of out-of-band channels is contrasted with the use of in-band channels (i.e., the same channels) that carry routine operational traffic. Out-of-band channels do not have the same vulnerability or exposure as in-band channels. Therefore, the confidentiality, integrity, or availability compromises of in-band channels will not compromise or adversely affect the out-of-band channels. Organizations may employ out-of-band channels in the delivery or transmission of organizational items, including authenticators and credentials; cryptographic key management information; system and data backups; configuration management changes for hardware, firmware, or software; security updates; maintenance information; and malicious code protection updates. For example, cryptographic keys for encrypted files are delivered using a different channel than the file.

## What to Check

- [ ] Verify SC-37 Out-of-band Channels is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SC-37

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-37 implementation details. Verify the organization has documented how this control is satisfied.

### Step 2: Validate Implementation

```
# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly

# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null
```

### Step 3: Test Operating Effectiveness

Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.

## Tools

| Tool            | Purpose                               | Usage                                |
| --------------- | ------------------------------------- | ------------------------------------ |
| cloud-audit-mcp | Check encryption and network controls | `cloud_audit_encryption`             |
| nmap            | Network scanning                      | `nmap -sV --script ssl-enum-ciphers` |

## Remediation Guide

### Control Statement

Employ the following out-of-band channels for the physical delivery or electronic transmission of [organization-defined] to [organization-defined]: [organization-defined].

### Implementation Guidance

Out-of-band channels include local, non-network accesses to systems; network paths physically separate from network paths used for operational traffic; or non-electronic paths, such as the U.S. Postal Service. The use of out-of-band channels is contrasted with the use of in-band channels (i.e., the same channels) that carry routine operational traffic. Out-of-band channels do not have the same vulnerability or exposure as in-band channels. Therefore, the confidentiality, integrity, or availability compromises of in-band channels will not compromise or adversely affect the out-of-band channels. Organizations may employ out-of-band channels in the delivery or transmission of organizational items, including authenticators and credentials; cryptographic key management information; system and data backups; configuration management changes for hardware, firmware, or software; security updates; maintenance information; and malicious code protection updates. For example, cryptographic keys for encrypted files are delivered using a different channel than the file.

## Risk Assessment

| Finding                                    | Severity | Impact                                          |
| ------------------------------------------ | -------- | ----------------------------------------------- |
| SC-37 Out-of-band Channels not implemented | High     | System and Communications Protection            |
| SC-37 partially implemented                | Medium   | Incomplete System and Communications Protection |

## CWE Categories

| CWE ID  | Title                                |
| ------- | ------------------------------------ |
| CWE-311 | Missing Encryption of Sensitive Data |

## References

- [NIST SP 800-53 Rev 5 - SC-37](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sc-37)
- [NIST SP 800-53A Rev 5 (Assessment Procedures)](https://csrc.nist.gov/pubs/sp/800/53/a/r5/final)
- [NIST SP 800-53 Rev 5 Full Catalog](https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final)

## Checklist

- [ ] Control documented in SSP
- [ ] Implementation evidence collected
- [ ] Operating effectiveness validated
- [ ] Continuous monitoring in place
- [ ] Related controls (AC-2, CM-3, CM-5, CM-7, IA-2) reviewed